#include <iostream>
#include <string>
#include <numeric>
#include <functional>

int main()
{
    std::string s1 = "agatgctagatttcg";
    std::string s2 = "agcctcccgatagcc";

    int diffs = std::inner_product(s1.begin(), s1.end(), s2.begin(), 0,
                                   std::plus<int>(), std::not_equal_to<char>());

    std::cout << "The number of pairwise mismatches: " << diffs << '\n';
}